I need a good combination to hunt open fields. Something that is deep and can cover some ground. I have an XL Pro and my least expensive option would be a 15 inch coil. But I wonder if it would be any deeper on bullets and buttons. I also thought a minelab advantage with a large coil or a silver umax with the 10 by 12 concentric. Target ID is not as important as depth but I would like to be able to tell deep stuff from shallow. I have a sovereign but don't think I can cover the area with the slow sweep speed. What's your opinion?